The freshness of produce is typically defined by the qualities of taste, texture and appearance. Due to certain physiological effects fruits and vegetables generally begin to deteriorate and lose their freshness at the time of harvest. Once harvested from the parent plant, the fruit or vegetable no longer has the immune-like system of the plant to combat bacteria, fungus and viruses which deteriorate the produce. A substantial percentage of fruit and vegetable harvests is thus lost due to such deterioration. Because of the immense size of the produce industry, it would be highly advantageous from an economic standpoint to preserve harvested produce in a savory, fresh condition for a longer period of time. Hence, many different methods for prolonging produce shelf life have been employed, with varying degrees of success.
Refrigeration has been the most popular method of increasing the useful life of fresh fruits and vegetables. By storing produce at a low temperature, it is possible to extend the freshness by retarding ripening, softening, textural changes and color changes. Lower temperatures also reduce undesirable metabolic changes, reduce moisture losses, and prevent undesirable growth on the produce. However, depending on the length of time the produce is chilled, refrigeration generally adversely affects taste and quality, and in the case of excessive or extreme chilling, may actually damage the produce due to chilling stresses.
Other methods of prolonging shelf life include coating the fruit or vegetable with a protective material, such as wax. However, the success of the coating is related not only to how well the coating protects the fruit or vegetable, but also how well it maintains a desirable appearance of the fruit or vegetable, without affecting its taste. Consequently, the success of this method has been limited. It has also been attempted to lengthen the shelf life of produce through heating to reduce the microorganism population, then refrigerating it at a desirable temperature. The success of this process has been limited in that shelf life has not been significantly increased. It has also been a common practice to harvest produce prior to ripening, then treating it with ethylene gas to effect ripening. This process has generally provided a low quality, unflavorful product, particularly in the case of tomatoes. Furthermore, the effects of deterioration begin at the time of harvest regardless of ripeness of the fruit or vegetable.
A more recent approach to increasing the shelf life of produce, and tomatoes in particular, has been the employment of genetic engineering techniques to decrease the rate in which tomatoes are affected by microorganisms. Such a process can be viewed as overly complicated to accomplish the goals of extended freshness, and has also enjoyed only limited success.
What is needed is a simple procedure for significantly increasing the shelf life of produce at a reasonable cost. It is therefore an object of the present invention to provide such a procedure.